Development of the Collimator System for the 3GeV Rapid Cycling Synchrotron

In order to localize the beam loss in the restricted area, the beam collimation system is prepared in the 3GeV Rapid Cycling Synchrotron (RCS) of the Japan Proton Accelerator Complex (J-PARC) Project. The amount of the localized beam loss on the one collimator is estimated about 1.2kW, and that loss generates a large quantity of the secondary radiations. So the beam collimator must be designed that it is covered with enough shielding. We calculated the radiation dose of the collimator and decided necessary shielding thickness. This result indicated that the residual dose rate at the outside surface of the shielding was mostly under 1mSv/h. We developed the remote cramp system and rad-hard components in order to reduce the radiation exposure during maintenance of the collimator. And also we coated The Titanium Nitride (TiN) film on the inside surface of the vacuum chamber in order to reduce the secondary electron emission from the collimator and the chamber surface. Now we investigate the possibility of another coating.