DESIGN STUDY OF THE INJECTION AND EXTRACTION ELE FOR THE RIKEN SUPERCONDUCTING RING C

The injection system for the RIKEN 6-sector superconducting ring cyclotron (SRC) consists of four bending magnets (BM1, BM2, BM3, BM4), three magnetic inflection channels (MIC1, MIC2, MIC3), and an electrostatic inflection channel (EIC). The four bending magnets and one of the three magnetic channels are superconducting. In this paper, the status of the design study of the BM1 is reported. 1 INTRODUCTION The injection and extraction systems of the RIKEN 6sector superconducting ring cyclotron (SRC) are designed. [1,2,3,4] It is required that the disturbance due to the bending magnets in the acceleration region should be less than 100 G. Two types of bending magnets - with an iron yoke or a shield coil - have been studied. A stray field up to 0.6 T is anticipated in the area of the BM1 due to the saturation of iron yoke of the main SRC's sector magnet, depending on ions. Then, if the BM1 has an iron yoke, the iron yoke saturates due to the stray field. Such saturation of the iron yoke was simulated by the field calculation, with 3D electromagnetic calculation code TOSCA, for the complete configuration of 6-sector magnets. As a result, it was found that the iron yoke is ineffective due to the stray fields of up to 0.6 T from the sector magnets, and an active-shield type magnet, which is equipped with shield coils, is adopted for the BM1 close to the sector magnets. The magnetic inflection channels are also designed to be an active shield type. In this paper, we discuss about the design of the injection bending magnet BM1, in particular about the optimization of the cross-sectional shape of the BM1. Major parameters of BM1 are shown in Table 1. Table 1. Major parameter of BM1 xw.0 xm.0