| Paper | Title | Page |
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| MOPGW036 | Studies on Coherent Multi-Bunch Tune Shifts with Different Bunch Spacing at the J-PARC Main Ring | 167 |
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| At a high-power proton synchrotron, betatron tune shifts induced by space charge effects cause beam loss which limits the beam intensity. To achieve further high beam intensity at the main ring of the Japan Proton Accelerator Research Complex, precise control of the tune shift is indispensable. When carrying out multi-bunch measurements, we observed that the dependence of the tune shift intensity on the number of bunches follow opposite slope trends for the horizontal and vertical directions. The influence of the bunch spacing was also observed. We report on a simplified tune shift model reconstruction for understanding the origin of these phenomena and present a correction of the tune shifts for reducing beam loss up to 30 %. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW036 | |
| About • | paper received ※ 01 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | |
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| MOPRB045 | Future High Power Proton Drivers for Neutrino Beams | 662 |
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Funding: ESSnuSB has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 7774. Over the last two decades, significant efforts were made through several international studies to identify and develop technical solutions for potential Neutrino Factories and Superbeam Facilities. With many questions now settled, as well as clearer R&D needs, various proposals are being made for future facilities in China, Europe, Japan and North America. These include both developing and adapting existing machines as well as green-field solutions. In this paper, we review all the major accelerator programmes aimed at delivering high-power proton beams for neutrino physics. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB045 | |
| About • | paper received ※ 22 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| WEPGW039 | Multi-Ribbon Profile Monitor for High Power Proton Beam at J-PARC MR Abort Line | 2561 |
| SUSPFO044 | use link to see paper's listing under its alternate paper code | |
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| Japan Proton Accelerator Research Complex (J-PARC) Main Ring (MR), the world-class high intensity proton synchrotron, provides proton beam to two experimental facilities with two extraction modes: Fast extraction (FX) and Slow extraction (SX). The number of protons per pulse (ppp) in MR recorded the world highest value of 2.6×1014 in the FX mode. Now we are planning to increase the ppp further up to 3.3×1014 in near future. The beam profile is one of the most important parameters to discuss the high intensity beam dynamics in MR. Monitors using multi-wires / ribbons are effective to measure the beam profile with good accuracy and wide dynamic range. However, they cause significant beam losses by interactions with high-intensity circulating beam in synchrotrons. Recently, we installed new multi-ribbon profile monitor (MRPM) in an abort line in MR. The abort line is one of the extracted beam lines of the FX system. It has a quadrupole doublet which is called Abort Q and transports extracted beam to a beam dump. The FX system can extract the circulating beam in MR with an arbitrary energy. Performing the single-pass measurement with MRPM and changing the transfer matrix by sweeping field strength of Abort Q, the emittance of the extracted beam can be measured. In this paper, we present the design, manufacturing, and results of the first beam test of newly installed MRPM system. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW039 | |
| About • | paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| WEPTS024 | Tune Shifts and Optics Modulations in the High Intensity Operation at J-PARC MR | 3148 |
| SUSPFO051 | use link to see paper's listing under its alternate paper code | |
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Funding: This study is supported by the MEXT program "Advanced Leading Graduate Course for Photon Science (ALPS)" J-PARC Main Ring (MR) is the intensity-frontier proton accelerator. The beam intensity of 2.6×1014 protons per pulse has been achieved for the current user operation. In this high-intensity operation, the tune spread caused by the space-charge is one of the main reasons for beam loss. The modulation of the betatron function and the tune shift were simulated with a PIC algorithm calculation code*. The simulation results showed that the space-charge effects were dominant in small particle action, and the sextupole fields effects were dominant in large particle action. Because sextupole strength is large in MR, sextupole fields induce substantial tune shifts. At the benchmark of the space-charge simulation, the simulation results matched the analytical space-charge calculations performed without sextupoles. It was found that the betatron function was modulated at most 6% by the space-charge effects and at most 8% by the effects of sextupoles in J-PARC MR. These effects to the injection beam optics matching and to the beam aperture will be investigated. * K. Ohmi et al., "Study of Halo Formation in J-PARC MR", Proceedings of the 22nd Particle Accelerator Conf. (PAC’07), Albuquerque, NM, USA, Jun. 2007, paper THPAN040, pp. 3318-3320. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS024 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | |
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