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@inproceedings{yasui:ipac2021-mopab229, author = {T.Y. Yasui and S. Igarashi and T. Koseki and Y. Kurimoto and Y. Morita and K. Ohmi and Y. Sato and T. Shimogawa}, % author = {T.Y. Yasui and S. Igarashi and T. Koseki and Y. Kurimoto and Y. Morita and K. Ohmi and others}, % author = {T.Y. Yasui and others}, title = {{Compensations of Third-Order Resonances in J-PARC MR}}, booktitle = {Proc. IPAC'21}, pages = {744--747}, eid = {MOPAB229}, language = {english}, keywords = {resonance, sextupole, operation, optics, survey}, venue = {Campinas, SP, Brazil}, series = {International Particle Accelerator Conference}, number = {12}, publisher = {JACoW Publishing, Geneva, Switzerland}, month = {08}, year = {2021}, issn = {2673-5490}, isbn = {978-3-95450-214-1}, doi = {10.18429/JACoW-IPAC2021-MOPAB229}, url = {https://jacow.org/ipac2021/papers/mopab229.pdf}, note = {https://doi.org/10.18429/JACoW-IPAC2021-MOPAB229}, abstract = {{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.}}, }