Design of ion optical system for high-precision carbon ion microsurgery beam line

Kamiya, Tomihiro; Oikawa, Masakazu*; Sato, Takahiro; Kashiwagi, Hirotsugu; Shimada, Hirofumi*; Arakawa, Kazuo; Yusa, Ken*; Nakano, Takashi*

The high-precision carbon ion microsurgery is a technique to irradiate a minute tumor or a small part of disease deep inside of the body by a beam of high-energy carbon ion focused down to a width of 100 m to 5 mm and with a positional accuracy of less than 1 mm. This challenging technique had been planned to be introduced to one of the irradiation ports of heavy-ion irradiation facility of Gunma University Heavy Ion Medical Center (GHMC). The beam transport system of the (vertical) port for the development of this technique was designed based on an ion optical calculation code, TRANSPORT. Aiming at adjusting the system to range shift of the ion beam for therapy, basic concept of this ion optical system was telescopic, achromatic, and analyzable of the energy of ion beams. Details of the ion optical calculation for the system will be presented.