Electron-optical system of a small-scale electron beam ion source

An electron-optical system (EOS) for a small-scale electron-beam ion source EBIS is developed. In this system,the axially symmetric focusing magnetic field of 3.6 kGs (Fig. ib) is formed by permanent magnets.EOS (Fig. la) consists of a diode electron gun with a fiat cathode 1. 1 mm in diameter, a drift structure I mm indiameter, and an electron collector with a suppressor. The EOS length from the cathode to the collector is 70 mm. Thecurrent of the electron beam reaches 10 mA for an energy of 2 to 3 keV.