Characterization of Ion Sources Introduction

24The development of ion sources started with the investigation of the canal rays by Goldstein in 1886. ¹ Later, electron-atom collisions were used to design low-current ion sources. Higher ion currents became available with the investigation of the arc discharge ion sources in the 1930s. In the 1940s the rf- and microwave-driven discharges were investigated for ion beam production. Historical reviews and bibliographies can be found in the works of von Ardenne, ² L. Vályi, ³ and R. Wilson and G. Brewer. ⁴ Various books are available on the physical and technological aspects of ion sources in general or with chapters on specific ion sources. ^{5 – 13}