eeFACT2018 - List of Keywords (synchrotron)

Paper	Title	Other Keywords	Page
TUOAB01	Dynamic Aperture Limitation Due to the Synchrotron Radiation from Quadrupole Magnets in very High Energy Colliders	radiation, quadrupole, betatron, resonance	46
	A.V. Bogomyagkov, S.A. Glukhov, E.B. Levichev, S.V. Sinyatkin BINP SB RAS, Novosibirsk, Russia
	In a lepton storage ring of very high energy (e.g. in the e⁺e^- Higgs factory) synchrotron radiation from quadrupoles constraints transverse dynamic aperture even in the absence of any magnetic nonlinearities. This was observed in LEP and the Future Circular e⁺e^- Collider (FCC-ee). Synchrotron radiation in the quadrupoles modulates the particle energy at the double betatron frequency. Energy modulation varies transverse focusing strength at the same frequency and creates a parametric resonance of the betatron oscillations. Starting from 6d equations of motion we derive and solve the relevant differential equation describing the resonance, and show good agreement between analytical results and numerical simulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUOAB01
About •	paper received ※ 11 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019
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TUYBA01	Benchmarking of Simulations of Coherent Beam-beam Instability	simulation, MMI, experiment, luminosity	103
	K. Ohmi, H. Koiso, Y. Ohnishi KEK, Ibaraki, Japan D. El Khechen CERN, Geneva, Switzerland K. Hirosawa Sokendai, Ibaraki, Japan
	Coherent beam-beam nstability 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. It is possible to observe the instability in SuperKEKB commissioning. Horizontal beam size blow-up of both beams has been seen depending on the tune operating point. We report the measurement results of the instability in SuperKEKB phaseII commissioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYBA01
About •	paper received ※ 25 September 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPBB04	Resonant Depolarization at Z and W at FCC-ee	polarization, resonance, ECR, collider	165
	I. Koop BINP SB RAS, Novosibirsk, Russia
	Both future 100 km in circumference electron-positron colliders CEPC and FCC-ee need know beams energies with the extreme precision of 1-2 ppm. This can be done only with the help of Resonant Depolarization (RD) technique. Still, some beam parameters of these machines, like energy spread and damping decrements, are so high near 80 GeV per beam, that it is required special consideration and tricks to overcome the difficulties. The author has written simple spin tracking code, which simulates main features of the RD process in presence of continuous energy diffusion due to synchrotron radiation fluctuations. It was shown by this study, that the applicability of the RD method is limited by the effect of widening of a width of the central peak of the spin precession spectrum when the synchrotron tune is chosen too low, say below 0.05. In this case spin precession lost its resonant nature due to overlap of the wide central spectrum peak with nearby synchrotron side bands. Dependencies of the spectrum peaks width from various beam parameters and a new RD-procedure recipe are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPBB04
About •	paper received ※ 12 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019
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WEXBA03	Beam Blowup due to Lattice Coupling/Dispersion with/without Beam-beam	emittance, resonance, lattice, coupling	207
	K. Oide, D. El Khechen CERN, Meyrin, Switzerland
	Funding: Work supported by JSPS KAKENHI Grant Number 17K05475. Also supported by the European Commission under project EuCARD–2, grant agreement 312453, and under the Horizon 2020, grant agreement 654166. A significant blowup of the vertical emittance is observed in particle tracking in lattices with random skew quadrupoles, even without beam-beam effects with the FCC-ee lattice at ttbar. A Vlasov model well explains the blowup, and agrees with the tracking. This effect will set an additional limit on the goal of tuning of the vertical emittance of the lattice of colliders, well below the value at the collision.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEXBA03
About •	paper received ※ 25 September 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

TUOAB01

Dynamic Aperture Limitation Due to the Synchrotron Radiation from Quadrupole Magnets in very High Energy Colliders

radiation, quadrupole, betatron, resonance

46

A.V. Bogomyagkov, S.A. Glukhov, E.B. Levichev, S.V. Sinyatkin
BINP SB RAS, Novosibirsk, Russia

In a lepton storage ring of very high energy (e.g. in the e⁺e^- Higgs factory) synchrotron radiation from quadrupoles constraints transverse dynamic aperture even in the absence of any magnetic nonlinearities. This was observed in LEP and the Future Circular e⁺e^- Collider (FCC-ee). Synchrotron radiation in the quadrupoles modulates the particle energy at the double betatron frequency. Energy modulation varies transverse focusing strength at the same frequency and creates a parametric resonance of the betatron oscillations. Starting from 6d equations of motion we derive and solve the relevant differential equation describing the resonance, and show good agreement between analytical results and numerical simulation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUOAB01

About •

paper received ※ 11 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019

Export •

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

TUYBA01

Benchmarking of Simulations of Coherent Beam-beam Instability

simulation, MMI, experiment, luminosity

103

K. Ohmi, H. Koiso, Y. Ohnishi
KEK, Ibaraki, Japan
D. El Khechen
CERN, Geneva, Switzerland
K. Hirosawa
Sokendai, Ibaraki, Japan

Coherent beam-beam nstability 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. It is possible to observe the instability in SuperKEKB commissioning. Horizontal beam size blow-up of both beams has been seen depending on the tune operating point. We report the measurement results of the instability in SuperKEKB phaseII commissioning.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYBA01

About •

paper received ※ 25 September 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019

Export •

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

TUPBB04

Resonant Depolarization at Z and W at FCC-ee

polarization, resonance, ECR, collider

165

I. Koop
BINP SB RAS, Novosibirsk, Russia

Both future 100 km in circumference electron-positron colliders CEPC and FCC-ee need know beams energies with the extreme precision of 1-2 ppm. This can be done only with the help of Resonant Depolarization (RD) technique. Still, some beam parameters of these machines, like energy spread and damping decrements, are so high near 80 GeV per beam, that it is required special consideration and tricks to overcome the difficulties. The author has written simple spin tracking code, which simulates main features of the RD process in presence of continuous energy diffusion due to synchrotron radiation fluctuations. It was shown by this study, that the applicability of the RD method is limited by the effect of widening of a width of the central peak of the spin precession spectrum when the synchrotron tune is chosen too low, say below 0.05. In this case spin precession lost its resonant nature due to overlap of the wide central spectrum peak with nearby synchrotron side bands. Dependencies of the spectrum peaks width from various beam parameters and a new RD-procedure recipe are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPBB04

About •

paper received ※ 12 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019

Export •

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

WEXBA03

Beam Blowup due to Lattice Coupling/Dispersion with/without Beam-beam

emittance, resonance, lattice, coupling

207

K. Oide, D. El Khechen
CERN, Meyrin, Switzerland

Funding: Work supported by JSPS KAKENHI Grant Number 17K05475. Also supported by the European Commission under project EuCARD–2, grant agreement 312453, and under the Horizon 2020, grant agreement 654166.
A significant blowup of the vertical emittance is observed in particle tracking in lattices with random skew quadrupoles, even without beam-beam effects with the FCC-ee lattice at ttbar. A Vlasov model well explains the blowup, and agrees with the tracking. This effect will set an additional limit on the goal of tuning of the vertical emittance of the lattice of colliders, well below the value at the collision.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEXBA03

About •

paper received ※ 25 September 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019

Export •

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