KEK, Ibaraki
The J-PARC accelerator comprises a 400 MeV linac, a 3-GeV Rapid Cycling Synchrotron (RCS) and a Main Ring (MR). In the linac, an H- ion beam was successfully accelerated to 181 MeV, the design target for the first step in Phase I, on January 24, 2007. Subsequently, full beam energy of 3 GeV was achieved in the RCS on October 31, 2007. The first beam commissioning of the MR was carried out in May and June 2008. Injection, circulation with rf capture and extraction to the injection beam dump were successfully performed. Some other basic tunings such as COD correction and chromaticity correction were also done well. In the MR, there are two extraction sections. One is for the Hadron Experimental Facility for which slow extraction will be mainly used and the other for neutrino experiment, which requires fast beam extraction. After confirming the basic performance of beam injection and beam circulation with rf capture, we have installed all devices for these two extraction sections and have progressed fine-tuning of ramp-up patterns of power supplies. Beam acceleration will start from December 2008. The first result of beam acceleration and extraction will be reported.
