Discharge and emission characteristics of a compact atomic and molecular hydrogen ion source

Abstract

The article describes the design and gives the discharge and emission characteristics of a compact hydrogen ion source based on a discharge with a hollow cathode initiated by a Penning-type discharge. The geometry of the discharge system is a modification of the rather well-known design of the plasma generator used in electron plasma sources and sources of “sputtering” ions. The discharge system of the ion source operates in a continuous mode, but is also capable of operating in a repetitively pulsed mode. The extraction and formation of the ion beam is carried out by a three-electrode optical system with an electrode cone-opening angle of 90°. The design of the ion-optical system makes it possible to operate at accelerating voltages up to 30 kV and form beams of protons and molecular hydrogen ions with current densities over 100 mA/cm2. In the continuous mode, a total ion beam current about 14 mA was obtained at a discharge current of 450~500 mA and with an emission diameter of 3.5 mm. Using a separator based on a bending electromagnet, detailed panoramic mass spectra of the ion beam were obtained for the first time for this ion source type. The discharge system of the plasma generator, the research results of which are presented in the article, is distinguished by its simple and compact design, a significant continuous operation resource, high reliability, low operating costs, etc.