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Electron cloud effects in SuperKEKB commissioning
/ Ohmi, K (KEK, Tsukuba ; Sokendai, Tsukuba) ; Flanagan, J (KEK, Tsukuba ; Sokendai, Tsukuba) ; Fukuma, H (KEK, Tsukuba ; Sokendai, Tsukuba) ; Ikeda, H (KEK, Tsukuba ; Sokendai, Tsukuba) ; Mulyani, E (KEK, Tsukuba ; Sokendai, Tsukuba) ; Shibata, K (KEK, Tsukuba ; Sokendai, Tsukuba) ; Suetsugu, Y (KEK, Tsukuba ; Sokendai, Tsukuba) ; Tobiyama, M (KEK, Tsukuba ; Sokendai, Tsukuba)
A vertical emittance growth (beam size blow-up) due to electron cloud has been observed in the positron low energy ring (LER) in Phase-I commissioning (2016) of SuperKEKB. The emittance growth is caused by fast head-tail instability due to wake force induced by electron cloud. [...]
2020 - 4 p.
Fulltext from publisher: PDF;
In : ECLOUD’18: Proceedings of the Joint INFN-CERN-ARIES Workshop on Electron-Cloud Effects, La Biodola, Isola d'Elba, Italy, 3 - 7 Jun 2018, pp.179-182 (CERN-2020-007)
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Benchmarking of Simulations of Coherent Beam-beam Instability with SuperKERKB Measurement
/ Ohmi, Kazuhito (KEK, Tsukuba) ; El Khechen, Dima (CERN) ; Hirosawa, Kouki (Sokendai, Tsukuba) ; Koiso, Haruyo (KEK, Tsukuba) ; Ohnishi, Yukiyoshi (KEK, Tsukuba)
Coherent beam-beam instability in head-tail mode has been predicted in collision with a large crossing angle. The instability is serious for design of future e⁺e⁻ colliders based on the large crossing angle collision. [...]
JACOW, 2019 - 3 p.
- Published in : 10.18429/JACoW-eeFACT2018-TUYBA01
Fulltext: PDF;
In : 62nd ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e− Colliders, Hong Kong, China, 24 - 27 Sep 2018, pp.TUYBA01
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3.
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4.
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Study of Electron Cloud Instabilities in FCC-hh
/ Ohmi, Kazuhito (KEK, Tsukuba) ; Mether, Lotta (CERN) ; Schulte, Daniel (CERN) ; Zimmermann, Frank (CERN)
Electron cloud effects are serious issue for LHC and future hadron colliders, FCC-hh. Electron cloud causes coherent instabilities due to collective motion between beam and electrons. [...]
CERN-ACC-2015-285.-
2015 - 3 p.
- Published in : (2015) , pp. TUPTY006
Published version from JACoW: PDF; External link: JACOW
In : 6th International Particle Accelerator Conference, Richmond, VA, USA, 3 - 8 May 2015, pp.TUPTY006
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5.
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Electron cloud effect and its cures in the SuperKEKB positron ring
/ Suetsugu, Y (KEK, Tsukuba) ; Fukuma, H (KEK, Tsukuba) ; Ohmi, K (KEK, Tsukuba) ; Tobiyama, M (KEK, Tsukuba) ; Shibata, K (KEK, Tsukuba)
Various countermeasures against the electron cloud effect (ECE) were adopted for the positron ring of SuperKEKB. During Phase-1 commissioning from February to June 2016, however, the ECE was observed, such as a blow up of the vertical beam size. [...]
2020 - 7 p.
Fulltext from publisher: PDF;
In : ECLOUD’18: Proceedings of the Joint INFN-CERN-ARIES Workshop on Electron-Cloud Effects, La Biodola, Isola d'Elba, Italy, 3 - 7 Jun 2018, pp.201-208 (CERN-2020-007)
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7.
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Wake Field and Head-Tail Instability in Beam-Beam Collision with a Large Crossing Angle
/ Ohmi, Kazuhito (KEK, Tsukuba) ; Kuroo, Nami (Unlisted, JP) ; Oide, Katsunobu (CERN) ; Zhou, Demin (KEK, Tsukuba) ; Zimmermann, Frank (CERN)
Head-tail type of coherent beam-beam instability has been seen in a strong-strong beam-beam simulation for collision with a large Piwinski angle σ_{z}θ/σ_{x}>>1, where θ is a half crossing angle. Beta x* is key parameter for the instability. [...]
CERN-ACC-2017-289.-
2017 - 3 p.
- Published in : 10.18429/JACoW-IPAC2017-THPAB021
Fulltext: PDF;
In : 8th International Particle Accelerator Conference, Copenhagen, Denmark, 14 - 19 May 2017, pp.THPAB021
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Coherent Beam-Beam Instability in Collisions with a Large Crossing Angle
/ Ohmi, K (KEK, Tsukuba) ; Kuroo, N (KEK, Tsukuba ; Tsukuba U. (main)) ; Oide, K (KEK, Tsukuba ; CERN) ; Zhou, D (KEK, Tsukuba ; CERN) ; Zimmermann, F (CERN)
In recent years the “crab-waist collision” scheme [P. Raimondi, Proceedings of 2nd SuperB Workshop, Frascati, 2006.; M. [...]
2017 - 5 p.
- Published in : Phys. Rev. Lett. 119 (2017) 134801
Fulltext: PDF;
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9.
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Mode Coupling Theory in Collisions With a Large Crossing Angle
/ Kuroo, Nami (Tsukuba U. ; KEK, Tsukuba) ; Hirosawa, Kouki (KEK, Tsukuba ; Tsukuba, Graduate U. Adv. Studies) ; Ohmi, Kazuhito (KEK, Tsukuba ; Tsukuba, Graduate U. Adv. Studies) ; Oide, Katsunobu (CERN) ; Zhou, Demin (KEK, Tsukuba) ; Zimmermann, Frank (CERN)
We discuss a novel coherent beam-beam instability in collisions with a large crossing angle. The instability appears in the correlated head-tail motion of the two colliding beams. [...]
CERN-ACC-2018-097.-
2018 - 3 p.
- Published in : 10.18429/JACoW-IPAC2018-THPAF089
Fulltext: thpaf089 - PDF; thpaf089_2 - PDF;
In : 9th International Particle Accelerator Conference, Vancouver, Canada, 29 Apr - 4 May 2018, pp.THPAF089
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10.
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Optics measurements and corrections at the early commissioning of SuperKEKB
/ Ohnishi, Y (KEK, Tsukuba, Kapan) ; Sugimoto, H (KEK, Tsukuba, Kapan) ; Morita, A (KEK, Tsukuba, Kapan) ; Koiso, H (KEK, Tsukuba, Kapan) ; Oide, K (KEK, Tsukuba, Kapan) ; Ohmi, K (KEK, Tsukuba, Kapan) ; Zhou, D (KEK, Tsukuba, Kapan) ; Funakoshi, Y (KEK, Tsukuba, Kapan) ; Carmignani, N (ESRF, Grenoble, France) ; Liuzzo, S M (ESRF, grenoble, France) et al.
We present experimental results of measurements and corrections for the optics at the early Phase-1 commissioning of SuperKEKB. The aim of SuperKEKB is a positron-electron collider built to achieve the target luminosity of 8x10^35 cm^−2s^−1. [...]
CERN-ACC-2017-0039.-
Geneva : CERN, 2017
- Published in : 10.18429/JACoW-IPAC2016-THPOR007
Fulltext: PDF;
In : 7th International Particle Accelerator Conference, Busan, Korea, 8 - 13 May 2016, pp.THPOR007
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