| Paper |
Title |
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| THDC1 |
Slow Extraction Operation at J-PARC Main Ring |
219 |
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- M. Tomizawa, Y. Arakaki, T. Kimura, S. Murasugi, R. Muto, H. Nishiguchi, K. Okamura, Y. Shirakabe, Y. Sugiyama, E. Yanaoka, M. Yoshii
KEK, Ibaraki, Japan
- K. Noguchi
Kyushu University, Fukuoka, Japan
- F. Tamura
JAEA/J-PARC, Tokai-mura, Japan
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A high-intensity proton beam accelerated in the J-PARC main ring (MR) is slowly extracted by using the third integer resonance and delivered to the experimental hall. A critical issue in slow extraction (SX) is a beam loss caused during the extraction. A dynamic bump scheme under an achromatic condition provides extremely high extraction efficiency. We have encountered a beam instability in the debunch formation process, which is estimated to be triggered by a longitudinal microstructure of the beam. To suppress this instability, the beam to the MR has been injected into the RF bucket with a phase offset. A newly developed RF manipulation, 2-step voltage debunch, has successfully pushed up the beam power up to 64.6 kW keeping a high extraction efficiency of 99.5%. A drastic beam loss reduction has been demonstrated in the beam test using a diffuser installed upstream of the first electrostatic septum (ESS1). 8 GeV bunched slow extraction tests for the neutrino-less muon to electron conversion search experiment (COMET Phase-I) have been successfully conducted.
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| DOI • |
reference for this paper
※ doi:10.18429/JACoW-HB2021-THDC1
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| About • |
Received ※ 18 October 2021 — Revised ※ 22 October 2021 — Accepted ※ 22 November 2021 — Issued ※ 03 December 2021 |
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| THDC2 |
Commissioning of the ESS Front End |
225 |
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- N. Milas, C.S. Derrez, E.M. Donegani, M. Eshraqi, B. Gålander, H. Hassanzadegan, E. Laface, Y. Levinsen, R. Miyamoto, M. Muñoz, E. Nilsson, D.C. Plostinar, A.G. Sosa, R. Tarkeshian, C.A. Thomas
ESS, Lund, Sweden
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The European Spallation Source, currently under construction in Lund, Sweden, will be the brightest spallation neutron source in the world, when the proton linac driver achieves the design power of 5 MW at 2 GeV beam energy. Such a high power requires production, efficient acceleration, and transport of a high current proton beam with minimal loss. This implies in a challenging design and beam commissioning of this machine. The linac features a long pulse length of 2.86 ms at a relatively low repetition late of 14 Hz. The ESS ion source and low energy beam transport are in-kind contributions from INFN-LNS. Beam commissioning of this section started in September 2018 and continued until early July in 2019. This article presents highlights from a campaign of beam characterizations and optimizations during this beam commissioning stage.
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| DOI • |
reference for this paper
※ doi:10.18429/JACoW-HB2021-THDC2
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| About • |
Received ※ 17 October 2021 — Revised ※ 20 October 2021 — Accepted ※ 22 November 2021 — Issued ※ 01 December 2021 |
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※ Text/Word,
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