Energy distribution of the compact microwave ion source for extremely low voltage ion extraction

Abstract

The energy distribution of the ion beam extracted from the compact microwaveion source for extremely low voltage ion extraction was measured with Ar and CO as a discharge gas. The energy distribution was measured by the retarding field method, and changes with respect to the change in gas pressure were observed. The obtained data were arranged by the peak energy and the energy spread. For both gases, the peak energy and the energy spread decreased with an increase in the gas pressure. The energy spread of approximately 5 eV with the peak energy of 15 eV were obtained for Ar gas at the pressure of 10[−2] Pa. For CO gas, the peak energy was higher than Ar and approximately 20 eV. The energy spread was 6 eV at the pressure of 10[−2] Pa. These values agreed with the peak energy and energy spread that were estimated previously from the mass spectraanalysis. Since the ion source was designed to be used in the researches of low energy ion-solid interaction, these characteristics satisfy the requirements for this purpose.