Emission current stabilizer to electron-impact gas ion sources

Abstract

We describe an electron emission current stabilizer with an error amplifier dc voltage gain depending on the electron emission current. A negative feedback loop of the error amplifier contains a solid-state digital potentiometer, which is controlled by a microprocessor according to the empirically determined (based on the Ziegler - Nichols method) exponential dc voltage gain function. The obtained mean relative standard deviation of the electron emission current, for a tungsten filament operated at the pressure of/?=0.1Pa, is 36 ppm.