Development of high current surface ionization sources for heavy ion fusion

Due to their intrinsic low ion temperature, surface ionization sources with a moderate to high current density (J/spl sim/10-100 mA/cm/sup 2/) may meet the beam brightness requirement for Heavy Ion Fusion (HIF) injectors, for both, the large source and multiple-beamlet designs. However, alkali metals released by these sources can contaminate and degrade high voltage insulators, thus making neutral atom loss an important issue. We present experimental results of average emitted J's and lifetime performance of K/sup +/ and Cs/sup +/ surface ionization sources and K-aluminosilicate sources operating in pulsed modes (2-10 /spl mu/s). Fabrication of large (/spl sim/10 cm diameter) aluminosilicate sources is challenging given the surface quality required. Current work in this aspect is presented.