IPAC2022 - Classification: MC1: Circular and Linear Colliders / A02: Lepton Colliders

Paper	Title	Page
MOPLXGD1	The SuperKEKB Has Broken the World Record of the Luminosity	1
	Y. Funakoshi, T. Abe, K. Akai, Y. Arimoto, K. Egawa, S. Enomoto, H. Fukuma, K. Furukawa, N. Iida, H. Ikeda, T. Ishibashi, S.H. Iwabuchi, H. Kaji, T. Kamitani, T. Kawamoto, M. Kikuchi, T. Kobayashi, K. Kodama, H. Koiso, M. Masuzawa, K. Matsuoka, T. Mimashi, G. Mitsuka, F. Miyahara, T. Miyajima, T. Mori, A. Morita, S. Nakamura, T.T. Nakamura, K. Nakanishi, H.N. Nakayama, M. Nishiwaki, S. Ogasawara, K. Ohmi, Y. Ohnishi, N. Ohuchi, T. Okada, T. Oki, M.A. Rehman, Y. Seimiya, K. Shibata, Y. Suetsugu, H. Sugimoto, H. Sugimura, M. Tawada, S. Terui, M. Tobiyama, R. Ueki, X. Wang, K. Watanabe, S.I. Yoshimoto, T. Yoshimoto, D. Zhou, X. Zhou, Z.G. Zong KEK, Ibaraki, Japan A. Natochii University of Hawaii, Honolulu,, USA K. Oide CERN, Meyrin, Switzerland R.J. Yang CAEP/IAE, Mianyang, Sichuan, People’s Republic of China K. Yoshihara Nagoya University, Nagoya, Aichi, Japan
	The SuperKEKB broke the world record of the luminosity in June 2020 in the Phase 3 operation. The luminosity has been increasing since then and the present highest luminosity is 4.65 x 10³⁴ cm^-2s^-1 with β_y^* of 1 mm. The increase of the luminosity was brought with an application of crab waist, by increasing beam currents and by other improvements in the specific luminosity. In this paper, we describe what we have achieved and what we are struggling with. Finally, we mention a future plan briefly.
	Slides MOPLXGD1 [6.235 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPLXGD1
About •	Received ※ 10 June 2022 — Accepted ※ 08 July 2022 — Issue date ※ 10 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUIZSP1	Status of the e⁺e⁻ Collider Projects in Asia and Europe: CEPC and FCC-ee	815
	X.C. Lou IHEP, Beijing, People’s Republic of China M. Boscolo LNF-INFN, Frascati, Italy F. Zimmermann CERN, Meyrin, Switzerland
	Since the Higgs boson discovery at CERN, precision measurement of its properties has become the first priority in the field of High Energy Physics. Two laboratories, CERN from Europe and IHEP from China, have proposed large scale circular electron-positron colliders, namely FCC-ee and CEPC. Record luminosities are expected in the center of mass energy range from 90 to about 365 GeV. In this talk the statuses of both projects are reviewed: Following the publication of the first CDR FCC-ee and CEPC entering the phase of consolidation and feasibility study. Special focus will be put on R&D plans, prototyping and key technologies.
	Slides TUIZSP1 [6.718 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUIZSP1
About •	Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOZSP1	Prospects for Optics Measuements in FCC-ee	827
	J. Keintzel, R. Tomás García, F. Zimmermann CERN, Meyrin, Switzerland
	Within the framework of the Future Circular Collider Feasibility Study, the design of the electron-positron collider FCC-ee is optimised, as a possible future double collider ring, currently foreseen to start operation during the 2040s. With close to 100 km of circumference and strong synchrotron radiation damping at highest beam energy, adequate beam measurements are needed to control the optics at the desired level. Various possible techniques to measure the optics in FCC-ee are explored, including the option of turn-by-turn measurements in combination with an AC-dipole.
	Slides TUOZSP1 [2.738 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUOZSP1
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 28 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOZSP2	Chromatic X-Y Coupling Correction by Tilting Sextupole Magnets in the SuperKEKB Positron Ring
	M. Masuzawa, K. Egawa, Y. Funakoshi, T. Kawamoto, H. Koiso, A. Morita, S. Nakamura, K. Ohmi, Y. Ohnishi, R. Sugahara, H. Sugimoto, R. Ueki, D. Zhou KEK, Ibaraki, Japan K. Oide CERN, Meyrin, Switzerland
	Chromatic x-y coupling correction at the interaction point was carried out using skew sextupole field created by tilting the sextupole magnets in the SuperKEKB positron ring. Twenty four sextupole magnets are mounted on a tilting table and their tilt angles can be varied form - 30 degree to + 30 degree remotely to control the ratio of the skew to normal sextupole magnetic field components. In the 2021c run, one of the chromatic coupling parameters was varied using different setups of the tilting angles of the 24 sextupole magnets for the first time in a collider. It was found that the emittance growth at the primary (nux-nuy-nus=n) and secondary (nux-nuy-2nus=n) synchro-beta resonance lines can be controlled by tilting the sextupole magnets. Luminosity increase followed after optimizing the chromatic coupling parameters and finding a better tune working point. The study results are summarized in the paper.
	Slides TUOZSP2 [19.499 MB]
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOZSP3	The European ERL Roadmap	831
	A. Hutton JLab, Newport News, Virginia, USA M. Klein The University of Liverpool, Liverpool, United Kingdom B.C. Kuske HZB, Berlin, Germany
	Funding: AH supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177 Following the European Strategy process in 2019, five Roadmap Panels were set up to prepare the technologies needed for future accelerators and colliders: high-field magnets, SRF, muon colliders, plasma wakefield accelerators and Energy Recovery Linacs (ERLs). The ERL Roadmap Panel, consisting of ERL experts from around the world, first developed an overview of current and future ERLs. From this it was possible to carry out a gap analysis to see what R&D would be needed, from which the Roadmap could be developed. The European ERL Roadmap focused on three main aspects: 1) the continuation and development of facility programs for which no additional funds are needed, S-DALINAC in Darmstadt and MESA in Mainz; 2) technology development for room-temperature HOM damping and twin-axis SRF cavities; 3) the timely upgrade of bERLinPro for 100 mA current and the construction of PERLE at Orsay as a dedicated 10 MW power multi-turn facility. The roadmap entails a vision of future energy frontier electron-positron and electron-hadron collider and describes a high quality ERL program for 4.4 K SRF technology at high Q₀. The presentation will address the ERL Roadmap process and result in detail.
	Slides TUOZSP3 [2.868 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUOZSP3
About •	Received ※ 02 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 29 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOXGD3	An Alternative Design for BEPCII Upgrade	1591
	H. Geng, J. Xing, C.H. Yu, Y. Zhang IHEP, Beijing, People’s Republic of China
	The Beijing Electron Positron Collider II (BEPCII) has achieved a series of achievements in high energy physics study. Along with the deepening of the research, more important physics is expected in higher energy region (>2.1 GeV). As the upper limit of BEPCII design energy is 2.1 GeV, an urgent upgrade is required for BEPCII. To achieve a higher luminosity at higher energy, the number of RF cavities is expected to be doubled. The baseline design which kept the survey of the North Collision Region (NCR) unchanged for the upgrade of BEPCII has been studied in previous work. In this paper, we show an alternative design that modifies the survey of NCR, but enables the online maintenance of both RF cavities in each ring of BEPCII. The dynamic aperture tracking result shows that the lattice could meet the injection requirement of BEPCII beam with reasonable margin.
	Slides WEOXGD3 [3.761 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXGD3
About •	Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 10 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOST001	Radiation Load Studies for Superconducting Dipole Magnets in a 10 TeV Muon Collider	1671
	D. Calzolari, C. Carli, B. Humann, A. Lechner, G. Lerner, F. Salvat Pujol, D. Schulte, K. Skoufaris CERN, Meyrin, Switzerland B. Humann TU Vienna, Wien, Austria
	Among the various future lepton colliders under study, muon colliders offer the prospect of reaching the highest collision energies. Despite the promising potential of a multi-TeV muon collider, the short lifetime of muons poses a severe technological challenge for the collider design. In particular, the copious production of decay electrons and positrons along the collider ring requires the integration of continuous radiation absorbers inside superconducting magnets. The absorbers are needed to avoid quenches, reduce the heat dissipation in the cold mass and prevent magnet failures due to long-term radiation damage. In this paper, we present FLUKA shower simulations assessing the shielding requirements for high-field magnets of a 10 TeV muon collider. We quantify in particular the role of synchrotron photon emission by decay electrons and positrons, which helps in dispersing the energy carried by the decay products. For comparison, selected results for a 3 TeV muon collider are also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST001
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 16 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOST002	Synchrotron Radiation Impact on the FCC-ee Arcs	1675
	B. Humann TU Vienna, Wien, Austria F. Cerutti, B. Humann, R. Kersevan CERN, Meyrin, Switzerland
	Synchrotron radiation (SR) emitted by electron and positrons beams represents a major loss source in high energy circular colliders, such as the lepton version of the Future Circular Collider (FCC-ee) at CERN. In particular, for the operation mode at 182.5 GeV (above the top pair threshold), its spectrum makes it penetrate well beyond the vacuum chamber walls. In order to optimize its containment, dedicated absorbers are envisaged. In this contribution we report the energy deposition studies performed with FLUKA to assess heat load, time-integrated dose, power density and particle fluence distribution in the machine components and the surrounding environment. Different choices for the absorber material were considered and shielding options for electronics were investigated. Furthermore, possible positions for the booster ring were reviewed from the radiation exposure point of view.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST002
About •	Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 03 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOST007	Centre-of-Mass Energy in FCC-ee	1683
	J. Keintzel, R. Tomás García, F. Zimmermann CERN, Meyrin, Switzerland A.P. Blondel DPNC, Genève, Switzerland D.N. Shatilov BINP SB RAS, Novosibirsk, Russia
	The Future Circular electron-positron Collider (FCC-ee) is designed for high precision particle physics experiments. This demands a precise knowledge of the beam energies, obtained by resonant depolarization, and from which the center-of-mass energy and possible boosts at all interaction points are then determined. At the highest beam energy mode of 182.5 GeV, the energy loss due to synchrotron radiation is about 10 GeV per revolution. Hence, not only the location of the RF cavities, but also a precise control of the optics and understanding of beam dynamics, are crucial. In the studies presented here, different possible locations of the RF-cavities are considered, when calculating the beam energies over the machine circumference, including energy losses from crossing angles, a non-homogeneous dipole distribution, and an estimate of the beamstrahlung effect at the collision point.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST007
About •	Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 27 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOST010	Controlling e⁺/e⁻ Circular Collider Bunch Intensity by Laser Compton Scattering	1695
	F. Zimmermann CERN, Meyrin, Switzerland T.O. Raubenheimer SLAC, Menlo Park, California, USA
	Funding: This project receives funding from the European Union’s H2020 Framework Programme under grant agreement no. 951754 (FCCIS). In the future circular electron-positron collider "FCC-ee", the intensity of colliding bunches must be tightly controlled, with a maximum charge imbalance between collision partner bunches of less than 3-5%. Laser Compton back scattering could be used to adjust and fine-tune the bunch intensity. We discuss a possible implementation and suitable laser parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST010
About •	Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 03 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOPT011	Modelling FCC-ee Using MADX	1854
	L. van Riesen-Haupt, H. Burkhardt, T.H.B. Persson, R. Tomás García CERN, Meyrin, Switzerland
	We present the latest developments for simulating FCC-ee using CERN’s MADX software. Along with updated benchmark studies, we describe how the latest MADX updates can facilitate the simulation of FCC-ee design features, including improvements in tapering and different options for implementing a tilted solenoid.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT011
About •	Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 08 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOPT017	First Optics Design for a Transverse Monochromatic Scheme for the Direct S-Channel Higgs Production at FCC-ee Collider	1878
	H.P. Jiang Harbin Institute of Technology (HIT) , Harbin, People’s Republic of China A. Faus-Golfe, Z.D. Zhang Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France K. Oide KEK, Ibaraki, Japan Z.D. Zhang IHEP, Beijing, People’s Republic of China Z.D. Zhang UCAS, Beijing, People’s Republic of China F. Zimmermann CERN, Meyrin, Switzerland
	The FCC-ee collider baseline foresees four different energy operation modes: Z, WW, H(ZH) and ttbar. An optional fifth mode, called s-channel Higgs production mode, could allow the measurement of the electron Yukawa coupling, in dedicated runs at 125 GeV centre-of-mass energy, provided that the centre-of-mass energy spread, can be reduced by at least an order of magnitude (5-10 MeV). The use of a special collision technique: a monochromatization scheme is one way to accomplish it. There are several methods to implement a monochromatization scheme. One method, named transverse monochromatization scheme, consists of introducing a dispersion different from zero but opposite sign for the two colliding beams at the Interaction Point (IP); In this paper we will report about the first attempt to design a new optics to implement a transverse monochromatic scheme for the FCC-ee Higgs production totally compatible with the standard mode of operation without dispersion at the IP.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT017
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 27 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOPT063	The FCCee Pre-Injector Complex	2007
	P. Craievich, B. Auchmann, S. Bettoni, H.-H. Braun, M. Duda, D. Hauenstein, E. Hohmann, R. Ischebeck, P.N. Juranič, J. Kosse, G.L. Orlandi, M. Pedrozzi, J.-Y. Raguin, S. Reiche, S.T. Sanfilippo, M. Schaer, N. Vallis, R. Zennaro PSI, Villigen PSI, Switzerland F. Alharthi, I. Chaikovska, S. Ogur Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France W. Bartmann, M. Benedikt, M.I. Besana, M. Calviani, S. Döbert, Y. Dutheil, O. Etisken, J.L. Grenard, A. Grudiev, B. Humann, A. Latina, A. Lechner, K. Oide, A. Perillo-Marcone, H.W. Pommerenke, R.L. Ramjiawan, Y. Zhao, F. Zimmermann CERN, Meyrin, Switzerland A. De Santis INFN/LNF, Frascati, Italy Y. Enomoto, K. Furukawa, K. Oide KEK, Ibaraki, Japan O. Etisken Kirikkale University, Kirikkale, Turkey C. Milardi LNF-INFN, Frascati, Italy T.O. Raubenheimer SLAC, Menlo Park, California, USA N. Vallis EPFL, Lausanne, Switzerland
	The international FCC study group published in 2019 a Conceptual Design Report for an electron-positron collider with a centre-of-mass energy from 90 to 365 GeV with a beam currents of up to 1.4 A per beam. The high beam current of this collider create challenging requirements on the injection chain and all aspects of the linac need to be carefully reconsidered and revisited, including the injection time structure. The entire beam dynamics studies for the full linac, damping ring and transfer lines are major activities of the injector complex design. A key point is that any increase of positron production and capture efficiency reduces the cost and complexity of the driver linac, the heat and radiation load of the converter system, and increases the operational margin. In this paper we will give an overview of the status of the injector complex design and introduce the new layout that has been proposed by the study group working in the context of the CHART collaboration. In this framework, furthermore, we also present the preliminary studies of the FCC-ee positron source highlighting the main requirements and constraints.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT063
About •	Received ※ 11 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 29 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOPT064	Simulations and Measurements of Luminosity at SuperKEKB	2011
	D. Zhou, Y. Funakoshi, K. Ohmi, Y. Ohnishi KEK, Ibaraki, Japan Y. Zhang IHEP, Beijing, People’s Republic of China
	The interplay of beam-beam interaction, machine imperfections, and beam coupling impedance makes it difficult to predict the luminosity performance of SuperKEKB. Since 2020, the crab waist scheme was introduced to SuperKEKB to suppress beam-beam resonances. The coherent beam-beam head-tail instability and beam-beam driven synchro-betatron resonances due to large crossing angle can drive horizontal blowup, which cannot be suppressed by crab waist. The longitudinal impedance modulates the synchrotron motion and therefore affects beam-beam instability. In this paper, we compare simulations and measurements of luminosity and discuss the challenges and direction toward developing a predictable luminosity simulation model for SuperKEKB.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT064
About •	Received ※ 13 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 30 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

The SuperKEKB Has Broken the World Record of the Luminosity

1

Y. Funakoshi, T. Abe, K. Akai, Y. Arimoto, K. Egawa, S. Enomoto, H. Fukuma, K. Furukawa, N. Iida, H. Ikeda, T. Ishibashi, S.H. Iwabuchi, H. Kaji, T. Kamitani, T. Kawamoto, M. Kikuchi, T. Kobayashi, K. Kodama, H. Koiso, M. Masuzawa, K. Matsuoka, T. Mimashi, G. Mitsuka, F. Miyahara, T. Miyajima, T. Mori, A. Morita, S. Nakamura, T.T. Nakamura, K. Nakanishi, H.N. Nakayama, M. Nishiwaki, S. Ogasawara, K. Ohmi, Y. Ohnishi, N. Ohuchi, T. Okada, T. Oki, M.A. Rehman, Y. Seimiya, K. Shibata, Y. Suetsugu, H. Sugimoto, H. Sugimura, M. Tawada, S. Terui, M. Tobiyama, R. Ueki, X. Wang, K. Watanabe, S.I. Yoshimoto, T. Yoshimoto, D. Zhou, X. Zhou, Z.G. Zong
KEK, Ibaraki, Japan
A. Natochii
University of Hawaii, Honolulu,, USA
K. Oide
CERN, Meyrin, Switzerland
R.J. Yang
CAEP/IAE, Mianyang, Sichuan, People’s Republic of China
K. Yoshihara
Nagoya University, Nagoya, Aichi, Japan

The SuperKEKB broke the world record of the luminosity in June 2020 in the Phase 3 operation. The luminosity has been increasing since then and the present highest luminosity is 4.65 x 10³⁴ cm^-2s^-1 with β_y^* of 1 mm. The increase of the luminosity was brought with an application of crab waist, by increasing beam currents and by other improvements in the specific luminosity. In this paper, we describe what we have achieved and what we are struggling with. Finally, we mention a future plan briefly.

Slides MOPLXGD1 [6.235 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPLXGD1

About •

Received ※ 10 June 2022 — Accepted ※ 08 July 2022 — Issue date ※ 10 July 2022

Cite •

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

TUIZSP1

Status of the e⁺e⁻ Collider Projects in Asia and Europe: CEPC and FCC-ee

815

X.C. Lou
IHEP, Beijing, People’s Republic of China
M. Boscolo
LNF-INFN, Frascati, Italy
F. Zimmermann
CERN, Meyrin, Switzerland

Since the Higgs boson discovery at CERN, precision measurement of its properties has become the first priority in the field of High Energy Physics. Two laboratories, CERN from Europe and IHEP from China, have proposed large scale circular electron-positron colliders, namely FCC-ee and CEPC. Record luminosities are expected in the center of mass energy range from 90 to about 365 GeV. In this talk the statuses of both projects are reviewed: Following the publication of the first CDR FCC-ee and CEPC entering the phase of consolidation and feasibility study. Special focus will be put on R&D plans, prototyping and key technologies.

Slides TUIZSP1 [6.718 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUIZSP1

About •

Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022

Cite •

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

TUOZSP1

Prospects for Optics Measuements in FCC-ee

827

J. Keintzel, R. Tomás García, F. Zimmermann
CERN, Meyrin, Switzerland

Within the framework of the Future Circular Collider Feasibility Study, the design of the electron-positron collider FCC-ee is optimised, as a possible future double collider ring, currently foreseen to start operation during the 2040s. With close to 100 km of circumference and strong synchrotron radiation damping at highest beam energy, adequate beam measurements are needed to control the optics at the desired level. Various possible techniques to measure the optics in FCC-ee are explored, including the option of turn-by-turn measurements in combination with an AC-dipole.

Slides TUOZSP1 [2.738 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUOZSP1

About •

Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 28 June 2022

Cite •

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

TUOZSP2

Chromatic X-Y Coupling Correction by Tilting Sextupole Magnets in the SuperKEKB Positron Ring

M. Masuzawa, K. Egawa, Y. Funakoshi, T. Kawamoto, H. Koiso, A. Morita, S. Nakamura, K. Ohmi, Y. Ohnishi, R. Sugahara, H. Sugimoto, R. Ueki, D. Zhou
KEK, Ibaraki, Japan
K. Oide
CERN, Meyrin, Switzerland

Chromatic x-y coupling correction at the interaction point was carried out using skew sextupole field created by tilting the sextupole magnets in the SuperKEKB positron ring. Twenty four sextupole magnets are mounted on a tilting table and their tilt angles can be varied form - 30 degree to + 30 degree remotely to control the ratio of the skew to normal sextupole magnetic field components. In the 2021c run, one of the chromatic coupling parameters was varied using different setups of the tilting angles of the 24 sextupole magnets for the first time in a collider. It was found that the emittance growth at the primary (nux-nuy-nus=n) and secondary (nux-nuy-2nus=n) synchro-beta resonance lines can be controlled by tilting the sextupole magnets. Luminosity increase followed after optimizing the chromatic coupling parameters and finding a better tune working point. The study results are summarized in the paper.

Slides TUOZSP2 [19.499 MB]

Cite •

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

TUOZSP3

The European ERL Roadmap

831

A. Hutton
JLab, Newport News, Virginia, USA
M. Klein
The University of Liverpool, Liverpool, United Kingdom
B.C. Kuske
HZB, Berlin, Germany

Funding: AH supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177
Following the European Strategy process in 2019, five Roadmap Panels were set up to prepare the technologies needed for future accelerators and colliders: high-field magnets, SRF, muon colliders, plasma wakefield accelerators and Energy Recovery Linacs (ERLs). The ERL Roadmap Panel, consisting of ERL experts from around the world, first developed an overview of current and future ERLs. From this it was possible to carry out a gap analysis to see what R&D would be needed, from which the Roadmap could be developed. The European ERL Roadmap focused on three main aspects: 1) the continuation and development of facility programs for which no additional funds are needed, S-DALINAC in Darmstadt and MESA in Mainz; 2) technology development for room-temperature HOM damping and twin-axis SRF cavities; 3) the timely upgrade of bERLinPro for 100 mA current and the construction of PERLE at Orsay as a dedicated 10 MW power multi-turn facility. The roadmap entails a vision of future energy frontier electron-positron and electron-hadron collider and describes a high quality ERL program for 4.4 K SRF technology at high Q₀. The presentation will address the ERL Roadmap process and result in detail.

Slides TUOZSP3 [2.868 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUOZSP3

About •

Received ※ 02 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 29 June 2022

Cite •

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

WEOXGD3

An Alternative Design for BEPCII Upgrade

1591

H. Geng, J. Xing, C.H. Yu, Y. Zhang
IHEP, Beijing, People’s Republic of China

The Beijing Electron Positron Collider II (BEPCII) has achieved a series of achievements in high energy physics study. Along with the deepening of the research, more important physics is expected in higher energy region (>2.1 GeV). As the upper limit of BEPCII design energy is 2.1 GeV, an urgent upgrade is required for BEPCII. To achieve a higher luminosity at higher energy, the number of RF cavities is expected to be doubled. The baseline design which kept the survey of the North Collision Region (NCR) unchanged for the upgrade of BEPCII has been studied in previous work. In this paper, we show an alternative design that modifies the survey of NCR, but enables the online maintenance of both RF cavities in each ring of BEPCII. The dynamic aperture tracking result shows that the lattice could meet the injection requirement of BEPCII beam with reasonable margin.

Slides WEOXGD3 [3.761 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXGD3

About •

Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 10 July 2022

Cite •

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

WEPOST001

Radiation Load Studies for Superconducting Dipole Magnets in a 10 TeV Muon Collider

1671

D. Calzolari, C. Carli, B. Humann, A. Lechner, G. Lerner, F. Salvat Pujol, D. Schulte, K. Skoufaris
CERN, Meyrin, Switzerland
B. Humann
TU Vienna, Wien, Austria

Among the various future lepton colliders under study, muon colliders offer the prospect of reaching the highest collision energies. Despite the promising potential of a multi-TeV muon collider, the short lifetime of muons poses a severe technological challenge for the collider design. In particular, the copious production of decay electrons and positrons along the collider ring requires the integration of continuous radiation absorbers inside superconducting magnets. The absorbers are needed to avoid quenches, reduce the heat dissipation in the cold mass and prevent magnet failures due to long-term radiation damage. In this paper, we present FLUKA shower simulations assessing the shielding requirements for high-field magnets of a 10 TeV muon collider. We quantify in particular the role of synchrotron photon emission by decay electrons and positrons, which helps in dispersing the energy carried by the decay products. For comparison, selected results for a 3 TeV muon collider are also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST001

About •

Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 16 June 2022

Cite •

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

WEPOST002

Synchrotron Radiation Impact on the FCC-ee Arcs

1675

B. Humann
TU Vienna, Wien, Austria
F. Cerutti, B. Humann, R. Kersevan
CERN, Meyrin, Switzerland

Synchrotron radiation (SR) emitted by electron and positrons beams represents a major loss source in high energy circular colliders, such as the lepton version of the Future Circular Collider (FCC-ee) at CERN. In particular, for the operation mode at 182.5 GeV (above the top pair threshold), its spectrum makes it penetrate well beyond the vacuum chamber walls. In order to optimize its containment, dedicated absorbers are envisaged. In this contribution we report the energy deposition studies performed with FLUKA to assess heat load, time-integrated dose, power density and particle fluence distribution in the machine components and the surrounding environment. Different choices for the absorber material were considered and shielding options for electronics were investigated. Furthermore, possible positions for the booster ring were reviewed from the radiation exposure point of view.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST002

About •

Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 03 July 2022

Cite •

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

WEPOST007

Centre-of-Mass Energy in FCC-ee

1683

J. Keintzel, R. Tomás García, F. Zimmermann
CERN, Meyrin, Switzerland
A.P. Blondel
DPNC, Genève, Switzerland
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

The Future Circular electron-positron Collider (FCC-ee) is designed for high precision particle physics experiments. This demands a precise knowledge of the beam energies, obtained by resonant depolarization, and from which the center-of-mass energy and possible boosts at all interaction points are then determined. At the highest beam energy mode of 182.5 GeV, the energy loss due to synchrotron radiation is about 10 GeV per revolution. Hence, not only the location of the RF cavities, but also a precise control of the optics and understanding of beam dynamics, are crucial. In the studies presented here, different possible locations of the RF-cavities are considered, when calculating the beam energies over the machine circumference, including energy losses from crossing angles, a non-homogeneous dipole distribution, and an estimate of the beamstrahlung effect at the collision point.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST007

About •

Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 27 June 2022

Cite •

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

WEPOST010

Controlling e⁺/e⁻ Circular Collider Bunch Intensity by Laser Compton Scattering

1695

F. Zimmermann
CERN, Meyrin, Switzerland
T.O. Raubenheimer
SLAC, Menlo Park, California, USA

Funding: This project receives funding from the European Union’s H2020 Framework Programme under grant agreement no. 951754 (FCCIS).
In the future circular electron-positron collider "FCC-ee", the intensity of colliding bunches must be tightly controlled, with a maximum charge imbalance between collision partner bunches of less than 3-5%. Laser Compton back scattering could be used to adjust and fine-tune the bunch intensity. We discuss a possible implementation and suitable laser parameters.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST010

About •

Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 03 July 2022

Cite •

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

WEPOPT011

Modelling FCC-ee Using MADX

1854

L. van Riesen-Haupt, H. Burkhardt, T.H.B. Persson, R. Tomás García
CERN, Meyrin, Switzerland

We present the latest developments for simulating FCC-ee using CERN’s MADX software. Along with updated benchmark studies, we describe how the latest MADX updates can facilitate the simulation of FCC-ee design features, including improvements in tapering and different options for implementing a tilted solenoid.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT011

About •

Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 08 July 2022

Cite •

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

WEPOPT017

First Optics Design for a Transverse Monochromatic Scheme for the Direct S-Channel Higgs Production at FCC-ee Collider

1878

H.P. Jiang
Harbin Institute of Technology (HIT) , Harbin, People’s Republic of China
A. Faus-Golfe, Z.D. Zhang
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
K. Oide
KEK, Ibaraki, Japan
Z.D. Zhang
IHEP, Beijing, People’s Republic of China
Z.D. Zhang
UCAS, Beijing, People’s Republic of China
F. Zimmermann
CERN, Meyrin, Switzerland

The FCC-ee collider baseline foresees four different energy operation modes: Z, WW, H(ZH) and ttbar. An optional fifth mode, called s-channel Higgs production mode, could allow the measurement of the electron Yukawa coupling, in dedicated runs at 125 GeV centre-of-mass energy, provided that the centre-of-mass energy spread, can be reduced by at least an order of magnitude (5-10 MeV). The use of a special collision technique: a monochromatization scheme is one way to accomplish it. There are several methods to implement a monochromatization scheme. One method, named transverse monochromatization scheme, consists of introducing a dispersion different from zero but opposite sign for the two colliding beams at the Interaction Point (IP); In this paper we will report about the first attempt to design a new optics to implement a transverse monochromatic scheme for the FCC-ee Higgs production totally compatible with the standard mode of operation without dispersion at the IP.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT017

About •

Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 27 June 2022

Cite •

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

WEPOPT063

The FCCee Pre-Injector Complex

2007

P. Craievich, B. Auchmann, S. Bettoni, H.-H. Braun, M. Duda, D. Hauenstein, E. Hohmann, R. Ischebeck, P.N. Juranič, J. Kosse, G.L. Orlandi, M. Pedrozzi, J.-Y. Raguin, S. Reiche, S.T. Sanfilippo, M. Schaer, N. Vallis, R. Zennaro
PSI, Villigen PSI, Switzerland
F. Alharthi, I. Chaikovska, S. Ogur
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
W. Bartmann, M. Benedikt, M.I. Besana, M. Calviani, S. Döbert, Y. Dutheil, O. Etisken, J.L. Grenard, A. Grudiev, B. Humann, A. Latina, A. Lechner, K. Oide, A. Perillo-Marcone, H.W. Pommerenke, R.L. Ramjiawan, Y. Zhao, F. Zimmermann
CERN, Meyrin, Switzerland
A. De Santis
INFN/LNF, Frascati, Italy
Y. Enomoto, K. Furukawa, K. Oide
KEK, Ibaraki, Japan
O. Etisken
Kirikkale University, Kirikkale, Turkey
C. Milardi
LNF-INFN, Frascati, Italy
T.O. Raubenheimer
SLAC, Menlo Park, California, USA
N. Vallis
EPFL, Lausanne, Switzerland

The international FCC study group published in 2019 a Conceptual Design Report for an electron-positron collider with a centre-of-mass energy from 90 to 365 GeV with a beam currents of up to 1.4 A per beam. The high beam current of this collider create challenging requirements on the injection chain and all aspects of the linac need to be carefully reconsidered and revisited, including the injection time structure. The entire beam dynamics studies for the full linac, damping ring and transfer lines are major activities of the injector complex design. A key point is that any increase of positron production and capture efficiency reduces the cost and complexity of the driver linac, the heat and radiation load of the converter system, and increases the operational margin. In this paper we will give an overview of the status of the injector complex design and introduce the new layout that has been proposed by the study group working in the context of the CHART collaboration. In this framework, furthermore, we also present the preliminary studies of the FCC-ee positron source highlighting the main requirements and constraints.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT063

About •

Received ※ 11 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 29 June 2022

Cite •

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

WEPOPT064

Simulations and Measurements of Luminosity at SuperKEKB

2011

D. Zhou, Y. Funakoshi, K. Ohmi, Y. Ohnishi
KEK, Ibaraki, Japan
Y. Zhang
IHEP, Beijing, People’s Republic of China

The interplay of beam-beam interaction, machine imperfections, and beam coupling impedance makes it difficult to predict the luminosity performance of SuperKEKB. Since 2020, the crab waist scheme was introduced to SuperKEKB to suppress beam-beam resonances. The coherent beam-beam head-tail instability and beam-beam driven synchro-betatron resonances due to large crossing angle can drive horizontal blowup, which cannot be suppressed by crab waist. The longitudinal impedance modulates the synchrotron motion and therefore affects beam-beam instability. In this paper, we compare simulations and measurements of luminosity and discuss the challenges and direction toward developing a predictable luminosity simulation model for SuperKEKB.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT064

About •

Received ※ 13 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 30 June 2022

Cite •

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