A. Kitagawa1), M. Muramatsu1), M. Sekiguchi1), S. Yamada1), T. Okada2), M. Yamamoto2), S. Biri3), and K. Uno4)
1) National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan,
2) Accelerator Engineering Corporation, 2-10-14 Konakadai, Inage, Chiba 263-0043, Japan,
3) Institute of Nuclear Research (ATOMKI), H-4001 Debrecen, P.O. Box 51, Hungary,
4) Sumitomo Heavy Industry, Ltd., 5-2 Soubiraki, Niihama, Ehime 792-8588, Japan.
Two ECR ion sources are installed for the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS). One of them, the NIRS-ECR, is a 10GHz ECR ion source, and is mainly operated to produce C4+ ions for the daily clinical treatment. The other source, the NIRS-HEC, is an 18GHz ECR ion source, and is expected to produce heavier ion species.
In order to realize the uniform ion-density distribution at the extraction aperture for the higher beam intensity, the radial magnetic field given by the permanent sextupole magnet has been optimized. In the case of the optimized magnetic configuration of the NIRS-HEC, the extracted intensities of Ar8+ and Ar9+ ions increased from 250 and 150 up to 800 and 400 electric micro A, respectively. An optimized sextupole magnet for the NIRS-ECR is under construction.
Other developments for increasing the beam intensity and extension of producible ion species are now in progress. An aluminum chamber, which is exchanged for the old copper chamber of the NIRS-HEC, has been tested. An additional microwave-injection system with a wide frequency range of 10 to 18GHz, which allows to investigate the effects of two-frequency heating, has been installed.
Presenting Author : Kitagawa A.
Presentation : Oral