AN IMPROVED EXTRACTION FOR THE MULTICUSP-TYPE LIGHT ION-ION SOURCE APPARATUS

new ion extraction system has been developed for use with the light io n source apparatus (LIISA) of the Accelerator Laboratory. The aim of t he new extraction system is to have a more intense and better quality beam. For simulation of the beam behavior at the extraction region a c omputer code IGUNe has been used. The simulation shows that a simple t riode extraction would be efficient enough to extract total beam inten sities of around 5 mA at an extraction voltage of 10-15 kV. At the sam e time, with the carefully designed plasma electrode, the emittance co uld be decreased significantly from the original design. The new extra ction was installed in May 1997 and the results have been encouraging. The transport efficiency of the extracted beam to the first Faraday c up (at a distance of 1.2 m) was 100% and the maximum proton current ob tained was 2.0 mA. The maximum proton current in the cyclotron inflect or is 1.0 mA, which is eight times larger than the previous record. (C ) 1998 American Institute of Physics.