Improvement the transmission of ion beams and replacement of charge analysis electromagnet coil at tandem accelerator

Ishizaki, Nobuhiro  ; Matsuda, Makoto  ; Hanashima, Susumu; Nakamura, Masahiko; Kutsukake, Kenichi ; Otokawa, Yoshinori  ; Asozu, Takuhiro  

The JAEA-Tokai folding-type tandem accelerator has been operated for 25 years. There are many optical devices at the terminal, such as a 180-degeree bending magnet (charge-analysis electromagnet) and electrostatic quadrupole lens, used for transporting ion beams from low-energy accelerating tubes to high-energy accelerating tubes. We have replaced the aged coil inside the 180-degeree bending magnet for a maintenance period of 2007. At this time, we have carried out the project to align the whole optical devices at the terminal. Precise measurement of the positions for these devices revealed that they were misaligned by 5 mm at the maximum deviation. By aligning these devices with the standard beam axis, we have improved the transmission of ion beams and increased beam currents with stable operation.