Construction of the superconducting ECR ion source venus

A new, very high magnetic field superconducting ECR ion source, VENUS, is u nder development at the LBNL 88-Inch Cyclotron. It will boost the maximum e nergies and intensities for heavy ions from the cyclotron particularly for ions with mass greater than 60. It will also serve as R&D ion source for th e proposed Rare Isotope Accelerator (RIA) project in the US, which requires up to 10 p muA of U30+. The superconducting magnet structure consists of t hree solenoids and six racetrack coils with iron poles forming the sextupol e. The coils are designed to generate a 4 Taxial mirror field at injection and 3 Tat extraction and a radial sextupole field of 2.4 Tat the plasma cha mber wall. Test results of the magnet coils, which exceeded design requirem ents with minimum training, are presented. The magnet assembly with its cry ostat will be enclosed by an iron shield and therefore must be designed to withstand any possible forces between coils and iron, which can be as high as 3.4.10(5) N (35,000 kgf). The low energy beam transport line (LEBT) and mass analyzing system of the ion source is designed to transport a proton-e quivalent current of 25 mA at 20 kV extraction voltage. The design of the i on source and LEBT will be discussed.