HIISI, New 18 GHZ ECRIS for the JYFL Accelerator Laboratory

At the end of 2013 the Academy of Finland granted an infrastructure funding for the JYFL Accelerator Laboratory in order to increase beam intensities for the international user community. The primary objective is to construct a new high performance ECR ion source, HIISI (Heavy Ion Ion Source Injector), for the K130 cyclotron. Using room temperature magnets the HIISI has been designed to produce about the same magnetic field configuration as the superconducting ECRIS SUSI at NSCL/MSU for 18 GHz operation. An innovative structure will be used to maximize the radial confinement and demagnetization safety margin of the permanent magnets. The sextupole magnet is separated and insulated from the plasma chamber providing two advantages: 1) the permanent magnet can be cooled down to -10˚C to increase its coercivity and 2) at the same time to reach slightly higher radial field on the inner surface of the plasma chamber. Comprehensive simulations were performed with the radial heat load to analyse and address all the heat loads and temperature distribution on the permanent magnet. This information is crucial to define the maximum plasma heating power and the grade of the permanent magnets. In this article the magnetic field design of HIISI and detailed innovative scheme for sextupole magnet will be presented.