Radiation shielding design for 300 keV ion implanter

PEFP (Proton Engineering Frontier Project) developed the 300 keV ion implanter for basic experiments. This facility, sponsored by ARTI (Advanced Radiation Technology Institute), was designed and manufactured for studies on a surface modification by an ion beam. Generally, in developing an ion implanter whose energy is around 300 keV or more, a shielding provision should be considered to prevent an unexpected exposure. During the development of PEFP's 300 keV ion implanter, its shielding issue was a localization of the shielding effect and the prevention of an acceleration of the secondary electrons by using a magnetic field, because it was needed to reduce X-ray more efficiently and the weight of the shielding material as well. In this paper, localization shielding concept was adopted and also a magnetic field was placed in the middle of an accelerator tube. Consequently, through this work, we reduced not only 30% of the X-ray intensity but also the weight of the shielding materials. (author)