IPAC2021 - List of Authors (Morita, Y.)

Paper	Title	Page
MOPAB229	Compensations of Third-Order Resonances in J-PARC MR	744
	T.Y. Yasui, S. Igarashi, T. Koseki, Y. Kurimoto, Y. Morita, K. Ohmi, Y. Sato, T. Shimogawa KEK, Tokai, Ibaraki, Japan
	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB229
About •	paper received ※ 20 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Compensations of Third-Order Resonances in J-PARC MR

744

T.Y. Yasui, S. Igarashi, T. Koseki, Y. Kurimoto, Y. Morita, K. Ohmi, Y. Sato, T. Shimogawa
KEK, Tokai, Ibaraki, Japan

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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB229

About •

paper received ※ 20 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)