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TY - CONF AU - Sato, Y. ED - Koscielniak, Shane ED - Satogata, Todd ED - Schaa, Volker RW ED - Thomson, Jana TI - High Power Beam Operation of the J-PARC RCS and MR J2 - Proc. of IPAC2018, Vancouver, BC, Canada, April 29-May 4, 2018 C1 - Vancouver, BC, Canada T2 - International Particle Accelerator Conference T3 - 9 LA - english AB - This invited talk presents the most recent status of improving J-PARC main ring (MR) beam operation together with the rapid cycling synchrotron (RCS) effort. The RCS has optimized the beam performance for the MR injection as well as the muon and neutron targets, where each requires different emittance and beam halo size. The MR has two extraction modes; fast extraction (FX) for the long baseline neutrino oscillation experiment, T2K, and slow extraction (SX) for experiments in the hadron experimental facility. At present, achieved beam intensities are 2.4·10¹⁴ protons per pulse (ppp) with cycle time 2.48 s (470 kW) in the FX mode and 5.10¹³ ppp with cycle time 5.52 s (44 kW) in the SX mode. For the FX operation, recent improvements are settings of new betatron tune, corrections of resonances near the betatron tune, and adopting 2nd harmonic rf voltage to reduce space charge effect. Beam instabilities have been suppressed with controlling chromaticity correction and transverse feedback systems. For the SX mode, a dynamic bump scheme for reducing extracted beam loss is successfully adopted. A high extraction efficiency of 99.5 % is achieved at the 44 kW beam operation. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2938 EP - 2942 KW - operation KW - extraction KW - emittance KW - quadrupole KW - betatron DA - 2018/06 PY - 2018 SN - 978-3-95450-184-7 DO - 10.18429/JACoW-IPAC2018-THYGBF1 UR - http://jacow.org/ipac2018/papers/thygbf1.pdf ER -