LIISA ion source

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- -Light Ion Source LIISA


Name and Model (Year of Manufacture / Installation)

LIISA light ion source unit (2000/2000)

General Information        

A filament driven light ion source for H- and d-. The ion source for cyclotrons and related instruments. The instrument can be used for example in the production of medical isotopes.

The K130 cyclotron in the University of Jyväskylä’s accelerator laboratory was originally designed for heavy ion acceleration. Many experiments however require proton beams, but the extraction efficiency of the cyclotron for protons is only about 50-70 %, which results in the activation of the cyclotron. This problem can be avoided by using H--beams and stripping extraction, which should give almost 100 % extraction efficiency. The medical isotope production at JYFL requires weekly 30 MeV proton beam with 30-50 µA intensity from the cyclotron. It corresponds only to 5.9 keV extraction energy out of the ion source. It was decided to convert the cyclotron to use H--acceleration and to build a new efficient H--ion source capable of producing 3 mA of H- at 5.9 keV. A filament driven multi-cusp source developed by Dr. Thomas Kuo at TRIUMF, Canada was selected. The source and beam extraction was designed and built at JYFL in collaboration with Dr. Kuo. It is called LIISA, as also our old positive multi-cusp source. The new LIISA replaced the old one in the injection line. A new light ions H- -multi-cusp source was constructed during Spring and Summer 2000.

Key Specifications    

Plasma chamber volume: 1.2 liters
Acceleration voltage:

  • 5.9 kV (30 MeV protons) 
  • 11.0 kV (60 MeV protons)

Base vacuum: 10 -6 mbar
Permanent magnets: 20 pcs, 10-line cusp field


Key Features    


Location, Contact Person

Department of Physics, YS 003 / Hannu Koivisto