Experimental Investigation of Ion Beam Extraction in Filament-Driven Negative-Carbon-Ion Sources With Various Geometrical Configurations for Accelerator Mass Spectrometry

Abstract

A negative carbon-ion source was designed for accelerator mass spectrometry for application in the medical field to minimize cross-contamination and to increase the measurement efficiency. The ion source was designed by adjusting the distance between the plasma and the extraction electrodes and by changing the anode structure. Various prototype ion source configurations were fabricated to construct an ion source test stand to confirm the carbon beam extraction. The transport efficiency of the negative carbon beam was experimentally investigated using a filament-driven ion source to determine the geometrical effect of the anode configuration. The carbonion source was operated under carbon dioxide gas flowing at 3.0 sccm at a high voltage of −30.0 kV and an applied arc current of up to 0.5 A and various magnetic fields. The optimized anode structure and operating conditions of the ion source with the beam characteristics must be verified to measure the beam current with various ion source parameters. The effects of various operating and structural conditions on the beam current are evaluated in this article.