Production of multiply charged fullerene and carbon cluster beams by a 14.5 GHz ECR ion source

Abstract

We report our first results on the study of normal and endohedral fullerene plasmas and beams produced by a 14.5 GHz electron cyclotron resonance (ECR) ion source (ECRIS). A mixed plasma of mainly N, N2, C, C2, and C60 was produced in the plasma chamber. Formation of caged nitrogens in the fullerene balls requires a careful, unusual tuning of the 14.5 GHz ECRIS. We deposited macroscopic quantities of the solid solution of N@C60 in C60 within the ECRIS. The N@C60/C60 ratio measured off-line using electron-spin-resonance spectroscopy may exceed typical values using conventional, non-ECR techniques. High intensities of C60Q+ ions (Q=1–5) were recorded in the extracted beam spectra. The highest measured C60+ beam current was 410 nA at 700 V extraction voltage. The method may be applied to produce carbon cluster beams from fullerenes, as well. We produced CnQ+ ions (n=2–15, Q=1,2) with intensities of 10–100 nA.