Design of the magnetic channels for the RIKEN superconducting ring cyclotron

Special designs have been adopted for the magnetic channels of the injection and extraction systems of the RIKEN Superconducting Ring Cyclotron (SRC). These magnetic channels are installed in the chambers between upper and lower coils of the sector magnets of the SRC, and superimpose additional magnetic fields on the base field of the sector magnets to inject or extract various beams. Maximum magnetic rigidity of the beam is considerably higher than that of conventional cyclotron, and the spaces to install the magnetic channels are limited by the size of the chambers and turn separation of the beams. Therefore powerful and compact magnetic channels are required. And besides, all magnetic channels were specified as normal-conducting magnets to reduce fabrication cost and to assure reliability. However, it is difficult to generate high magnetic fields by conventional normal-conducting magnetic channels with conductors only. Therefore, novel designs for powerful and compact normal-conducting magnetic channels were devised by use of iron as efficiently as possible. Detail designs are in progress.