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TY - CONF AU - Yasui, T.Y. AU - Igarashi, S. AU - Koseki, T. AU - Kurimoto, Y. AU - Morita, Y. AU - Ohmi, K. AU - Sato, Y. AU - Shimogawa, T. ED - Liu, Lin ED - Byrd, John M. ED - Neuenschwander, Regis T. ED - Picoreti, Renan ED - Schaa, Volker R. W. TI - Compensations of Third-Order Resonances in J-PARC MR J2 - Proc. of IPAC2021, Campinas, SP, Brazil, 24-28 May 2021 CY - Campinas, SP, Brazil T2 - International Particle Accelerator Conference T3 - 12 LA - english AB - The main ring synchrotron (MR) of the Japan Proton Accelerator Research Complex (J-PARC) provides high-power proton beams for the neutrino and hadron experiments. In the fast extraction (FX) operation, the beams are injected with the energy of 3 GeV and the intensity of 3.3 × 10¹³ protons per bunch, and accelerated to 30 GeV. Most of the beam losses are observed in the low-energy period, because the space charge tune spread is large, and crosses various kinds of resonances. In this study, the compensations of the third-order resonances are performed. The present operation tune is (ν_{x}, ν_{y}) = (21.35, 21.43) in FX operation. The nearest third-order structure resonance is ν_{x}-2ν_{y}=-21. It was clearly compensated by optimizing the phase advances in the arc sections. The compensation was confirmed by the aperture survey simulations and demonstrated by the three different experiments. The third-order nonstructure resonances near the operation tune are 3ν_{x}=64 and ν_{x}+2ν_{y}=64. They are simultaneously compensated by introducing four trim coils of the sextupole magnets. The beam loss was successfully reduced by adopting the compensations. PB - JACoW Publishing CP - Geneva, Switzerland SP - 744 EP - 747 KW - resonance KW - sextupole KW - operation KW - optics KW - survey DA - 2021/08 PY - 2021 SN - 2673-5490 SN - 978-3-95450-214-1 DO - doi:10.18429/JACoW-IPAC2021-MOPAB229 UR - https://jacow.org/ipac2021/papers/mopab229.pdf ER -