Radiation-Resistant Magnets for J-PARC

A series of construction works of the radiation resistant magnets for the Japan Proton Accelerator Research Complex (J-PARC) external beam facilities is now at the production and installation stage. The main accelerator of J-PARC is the 50 GeV proton synchrotron (50 GeV-PS). The designed intensity of the extracted proton beam from the 50 GeV-PS is 15 muA, i.e. a beam power of 750 kW. Then the radiation-resistant magnets are the key apparatus to construct the external beam lines and experimental facilities of the J-PARC 50 GeV-PS. The radiation-resistant magnets we have foreseen are approximately 50 magnets with Polyimide resin Insulation (PI) for radiation dose up to 10 Gy, and 20 magnets with completely Mineral Insulation Cable (MIC) for higher radiation dose up to 1011 Gy. Most of those magnets have already been fabricated and are waiting for being installed in primary and secondary beam lines. The installation will be completed by the middle of 2008. All the magnets are placed on the plug-in base assembled with water and electric-power quick disconnect devices. A new remote handling system of beam line magnets named "Chimney" has been developed and employed for magnets placed at the highest radiation area near the production target. The first beam will be introduced to the experimental area by the end of 2008.