Construction of Duoplasmatron Ion Source for the KEK-PS

Some new features of our ion source system are described: (1) Organic material is excluded from the vaccum seals and electric insulation in the discharge chamber. (2) A simple quick exchange mechanism of the cathode and source body was developed, because the 3 m long accelerating column requires the source to be mounted 1.4 m deep inside the column from its end plate. The source body is drived into the proper position by small ball bearings. The sealing force for vacuum is transmitted from a handle through a long pipe of small diamter to the 0-ring. (3) The arc modulator fully uses transistors and a small pulse transformer. Experimental results on the nozzle type plasma cup are summarized leading to a conclusion about advantages of this type of cup. Finally, performances of the source in the column is briefly described.