T. Tominaka

Design of the sector magnets for the RIKEN superconducting ring cyclotron

Design study of the superconducting sector magnets for the RIKEN superconducting ring cyclotron is described. Structures, magnetic forces, superconducting coils and a cryogenic system are discussed. Special features are, the cold pole arrangement, the supporting structure for huge magnetic forces, and the cryogenic stable coils.

Sector magnets for the RIKEN superconducting ring cyclotron

The sector magnets of the K2500-MeV superconducting ring cyclotron (SRC), which is under construction for the RIKEN RI beam factory, are described. The SRC consists of six sector magnets, four rf resonators, etc. each sector magnet is 7.2 m in length and 6 m in height and 800 t (metric ton) in weight; the sector angle is 25 deg. The required maximum magnetic field is 3.8 T. the superconductor for the main and trim coil has a rectangular shape (8 mm by 15 mm) consisting of a Rutherford-type NbTi cable located at the center of an Al-alloy stabilizer housing. The main coil is bath-cooled and the trim coil is directly cooled. Each component of the sector magnet as well as the cryogenic cooling system was completed in the spring of 2003.

Superconducting bending magnet for the RIKEN superconducting ring cyclotron

K2500 - superconducting ring cyclotron with 6-sectors is being constructed at RIKEN as one of the energy booster of the existing K540 ring cyclotron. The bending magnet for beam injection should be superconducting. Required fields are 3.8 T and radius of the coils is 1.2 m. After the fabrication, it was cooled down and excited. The magnet reached the designed field with one quench and training effect were clearly observed, which shows that it will works well to inject the beam into the superconducting cyclotron.

Quench analysis of RIKEN superconducting ring cyclotron

For the design of the protection system of the superconducting main coils of the RIKEN superconducting ring cyclotron, the quench characteristics is calculated in terms of current decay, temperature rise, voltage development etc., using the computer program QUENCH-M. The AC losses and pressure rise pertaining the quench are also estimated.

Design of structure and quench-stability of sector magnets for RIKEN superconducting ring cyclotron

Design, especially about the structure and quench stability, of the superconducting sector magnets for the RIKEN superconducting ring cyclotron is described. Special features of the sector magnets are the triangular shape superconducting coil, cold pole arrangement for supporting of the huge magnetic forces and the cryogenic stable coils. A full-scale superconducting model is now under construction as a prototype sector magnet.

Design study of the injection and extraction systems for the RIKEN superconducting ring cyclotron

In the RI beam factory project, an intermediate-stage ring cyclotron and a six-sector superconducting ring cyclotron (IRC and SRC) are designed to boost the energy of the ion beams available from the existing RIKEN ring cyclotron (RRC). The output energies designed to the SRC are 400 MeV/u for light ions such as carbon and are 150 MeV/u for heavy ions such as uranium. In the present report, we describe the recent status of design study of the injection and extraction systems for the SRC.