KEK, Tokai, Ibaraki, Japan
WEXB02
KEK, Ibaraki, Japan
KEK, Ibaraki, Japan
The University of Tokyo, Graduate School of Science, Tokyo, Japan
KEK, Ibaraki, Japan
| Paper | Title | Page |
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| MOPAB229 | Compensations of Third-Order Resonances in J-PARC MR | 744 |
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| 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 (νx, νy) = (21.35, 21.43) in FX operation. The nearest third-order structure resonance is νx-2νy=-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 3νx=64 and νx+2νy=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 | |
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WEXB02 |
Upgrading J-PARC Accelerator for Hyper Kamiokande Project | |
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| The Main Ring (MR) of J-PARC has supplied high-intensity proton beams for the T2K long-baseline neutrino oscillation experiment since 2010. The present beam power reaches 515 kW. To observe the CP violation in the lepton sector, more protons need to be delivered to the neutrino target. The project upgrading the beam power to 1.3 MW started in the MR, where hardware upgrades and beam dynamics improvements are scheduled to handle higher repetition and increase protons per pulse. The MR upgrade and the Hyper Kamiokande project, which has recently been approved and started construction, will open up a new phase of leptonic CP violation studies. | ||
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Slides WEXB02 [3.505 MB] | |
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| WEPAB204 | Layout of the New Septum Magnets for Fast Extraction in J-PARC Main Ring | 3103 |
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| At J-PARC Main Ring (MR), we are pursuing to improve the beam power from 500 kW to 1.3 MW by reducing the repetition cycle from 2.48 to 1.16 seconds (1 Hz operation). Additionally, we are considering the beam particles increasing by selecting a more optimal tune. The fast extraction (FX) equipment to the neutrino facility (NU) is needed to upgrade for the 1 Hz operation. We plan to replace most FX septum magnets with new ones in 2021. We report a layout of the FX line in confirmation of new beam optics and mention the beam loss during the fast extraction. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB204 | |
| About • | paper received ※ 20 May 2021 paper accepted ※ 09 June 2021 issue date ※ 27 August 2021 | |
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| THPAB245 | A Simulation Study of Beam Pipe Eddy Current Effects on Beam Optics | 4288 |
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| In synchrotrons, fast changes of magnetic field induce eddy currents at the wall of beam pipes. The eddy currents cause a phase delay between excitation currents of the magnets and the magnetic field. The undesired magnetic field affected by eddy currents might be a serious obstacle in controlling beam optics precisely. In fact, in the operation of a high-intensity proton synchrotron J-PARC MR, the largest beam loss is observed at the beginning of acceleration when the magnetic field starts to vary in time. Therefore, it is important to estimate and understand the effects of eddy currents on beam optics. In this study, we have calculated the effect of eddy currents on magnetic field for some magnets in J-PARC MR, using electromagnetic simulation software. In this paper, we would like to report the details and results of the simulation. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB245 | |
| About • | paper received ※ 19 May 2021 paper accepted ※ 26 July 2021 issue date ※ 17 August 2021 | |
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